Got Tin Whiskers?

摘要

The potential for "tin whisker" growths on component lead plating, solder and solder paste skyrocketed along with the industry's lead-free transition little more than a year ago. What might surprise you, though, is that tin whiskers aren't wreaking as much havoc as initially expected — yet.rnWhat are tin whiskers? NASA has been studying tin whiskers for many years and defines them as electrically conductive crystalline structures of tin that can grow from surfaces where tin (often electroplated tin) is used as a final finish. Tin whiskers are typically shown as having the shape of a very thin, single filament or hair-like protrusion that emerges outward (Z axis) from the surface (Figure). And they can cause electronic system failures by bridging closely spaced circuit elements maintained at different electrical potentials. Most frustrating, the exact causes, conditions and time frames involving tin whisker formation remain unknown.